The Backbone Of Space Invaders Extreme On Xbox Live Arcade

After being released on two portable platforms Space Invaders Extreme is out on Xbox Live Arcade with new visualizers and online modes. Now you can zap aliens with online friends! Backbone Entertainment handled the conversion and Arvin Bautista, Senior Artist, details the process of transitioning the PSP game to Xbox Live Arcade.

What code did Backbone Entertainment adapt to make Space Invaders Extreme for Xbox Live Arcade?

Arvin Joel M. Bautista, Senior Artist: We based the XBLA version off of the PSP version of the game. The screen ratio and gameplay just seemed to be a better fit than the DS for the home console.

How was the conversion done?

The engineer for the game, Kevin Pickell faithfully transferred the PSP engine over to the Xbox. Once we perfected that base, engineering, design and art added a variety of changes from top to bottom. These added features range from fleshing out a robust networking experience, designing new multiplayer modes, all the way to upresing, correcting, and adding in new art.

What was the most difficult part of Space Invaders Extreme to transition?

Believe it or not, the art staff had a hard time trying to get a nice crisp straight line to display! There’s a process in most of today’s next gen consoles called bi-linear filtering. What this does is it takes any harsh edges displayed and smoothes it out a little to make the edges softer, usually when something is scaled up or down.

In our case, we actually wanted the invaders to have that crisp, harsh edge, but instead they kept getting ‘smoothed out’. So the other artist, Conrad Seto, and I went through each of these cases and manually tweaked the art. I’d like to think we did a fairly good job, but it sure was a laborious task for something that most people won’t even see!

The Xbox Live Arcade release has new bosses and stages. Can you tell us about them?

This definitely isn’t your father’s Space Invaders (or in my case, ‘my old’ space invaders)! The classic Space Invaders had no boss battles to break up its stages. But in the extreme version we have five. Each is very distinct in behavior and appearance, but still pay homage to the original invaders.

The first one you’ll encounter is a large invader made up of separate blocks. In the upper middle are of the invader is a glowing gem that serves as his weakpoint. It’s up to the player to shoot through all those blocks, and expose the weakpoint all while dodging the boss’ shots. There are a few more creative bosses in there with even trickier patterns, but I wouldn’t want to ruin those surprises!

When the player is done playing through the initial stages in the arcade mode, an Extreme mode opens up. This mode features a whole new 5 levels with different layouts, alien behavior, music and visualizers.

There are also a couple of cool details about our art. In addition to our graphics being HD at 1080p, was that the invaders in this version of extreme are pixel perfect—meaning they match the exact dimensions of the characters in the classic arcade game. The DS and PSP versions had slightly different looking invaders from the classic game, I’m guessing to fit them onto the handheld displays better.

At the time of production however, we didn’t know this. We were so careful to stay true to the assets from the DS and PSP versions, we didn’t realize that something was amiss! After one look, Taito pointed it out to us when they came to visit, and supplied us with the original sprites to base our new HD ones off of. It was definitely a treat to get my hands on the original sprite sheet from the classic arcade game!

Anything about the new online modes? How are these different than the online play included in the Nintendo DS version?

Our multiplayer modes offer co-op and versus play for up to four players. And all of these modes can be played online or locally offline. Each Multiplayer mode has its own separate leaderboard to keep track of where you rank among your friends or worldwide. So while you may be top ranked at the single player leaderboard, you and your friends might not be so hot on the co-op ones!

Co-op mode has Arcade and Endless mode. Arcade lets all the players play through the stages in the single player mode together. So if you’re having a hard time beating some of those stages by yourself bring some of your buddies along and take those invaders down! Endless mode is definitely for the leaderboard hounds–just how long can you last blasting those invaders?

Versus mode consists of Practice, Score Attack and Survivor. Practice just lets you play through versus mode with a CPU, with no real consequences. This way you can hone your skills before you go out on Xbox Live. Score attack throw you and your buddies on one screen, playing through the single player stages, but the difference here is that each player has their own combo meter, life and score. Whoever gets the highest score wins!

Lastly, we have survivor mode (the studio favorite). Players get their own wave of aliens to fend off, but for every three aliens you shoot, one is sent into your ‘queue.’ You can store up to twelve aliens in your queue. Shooting a passing UFO will send over whatever’s in your queue to all of your opponents! Depending on which UFO you shot, it’ll change what invaders you sent over to them.

How did Jeff Minter get involved with the project?

Jeff Minter just seemed like a good fit for this project. He’s worked on titles like Defender 2000, Tempest 2000 and Space Giraffe, so it seemed like a logical progression.

Jeff crafted some excellent visualizers for us to replace the old backgrounds with. With these visualizers, I think the player is immersed into the game and the sound a whole lot more. Each visualizer reacts to the beat of the music, so for example, making the stars pulse or pushing buildings up and down like an equalizer. Along with that the visualizers will change its look depending on how hectic the pace of the game gets. So say in the beginning of a stage it’s the planet Earth, but as you whittle down a wave to just one last invader, the Earth starts having a flame effect on it, and the stars turn redder.

I remember being nervous working with Jeff, with all the stuff he’s done, I didn’t know how to work with him! Was he just going to do his thing and we just stand back? But once we got started he was very accommodating. He appreciated the feedback that we were giving him with each iteration of the visualizers, and we were very happy with the work he’d turn in. He made so much more than we required, that we decided to try to fit them all into the game, so you’ll see a lot of diverse visualizers running through it.

What kind of visualizers did he add?

Taito wanted us to follow some guidelines with the backgrounds for each of the five levels. Certain themes were picked so that they implied a journey of the invaders travelling from space to Earth. The themes are (in order of progression), Universe, (above the) Earth, Nature (landing in the atmosphere), Tokyo day and Tokyo night.

Jeff made the visualizers so that they walk the line between the real and the abstract. My personal favorites are the visualizers Jeff did for the Nature theme. It’s the most organic looking of all the visualizers.

The PSP and Nintendo DS versions of Space Invaders Extreme have different background music.

Which soundtrack does the Xbox Live Arcade version use?

The soundtrack is pretty much from the PSP version, with a different soundtrack per ‘difficulty’ you choose during the game. Our single player levels have a branching path that lets the player customize the difficulty as they progress. Somewhat like the branching paths you see in Outrun, at the end of each stage, you’re given a choice to choose the easier route or the more difficult one.